This modified Dan Armstrong came up for sale in November 2014 and ultimately sold for $1,920 after receiving numerous bids. The guitar looks very clean, but has been modified with a tune-o-matic bridge and stop tailpiece. One nice thing is an OEM case with the first-generation handle, which is a little unusual on a guitar with a serial number in the 500's.
"HERE IS A SUPER RARE GUITAR! CHECK OUT THIS AWESOME DAN ARMSTRONG AMPEG WITH THE CLEAR BODY! YOU DONT SEE THESE EVERYDAY! THERE ARE SOME SCRATCHES ON THE BODY. THE ACTION IS GOOD AND THE NECK PLAYS SMOOTH.THE TONE IS GREAT AS WELL. THIS ONE COMES WITH TWO PICKUPS AS THE PICK UPS ARE INTERCHANGEABLE IN THIS MODELS. THE BRIDGE HAS BEEN CHANGED AS YOU CAN SEE IN THE PICTURES. IT COMES WITH A HARDSHELL CASE. DONT MISS OUT ON THIS RARE GEM!"
Regarding the serial number, the seller didn't want to publish the entire number, but did disclose it as "SERIAL NUM. A53XX" in the original listing. When we asked to get the entire number for dating purposes, seller replied "Hey, the serial is A three numbers and then D. The full serial is only disclosed to the winner of the guitar. Thanks, guitar_steve."
So reading between the lines, we can narrow down the serial number to A53xD, which is accurate enough to let the buyer know this an earlier 1969 guitar, which is also confirmed by the early-style case. The extra pickup (not shown) is a Country Bass, suggesting that the pickup currently in the guitar is a Rock Treble.